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Thread: [[URGENT]] VBA help with the Taylor Series on Trigonometry

  1. #1
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    [[URGENT]] VBA help with the Taylor Series on Trigonometry

    Hello, I am new to this forum and I have an urgent problem to be solved. I hope someone here can help me out in writing a VBA While Loop on the Sine x function of the Taylor Series.

    the function that i need to write is something like this:

    h ttp://upload.wikimedia.org/math/5/d/3/5d32785481dec2be0c115f510f164dd1.png


    So far I have written a few lines. And my program is like the following:

    Function sum()

    Dim x() As Double
    Dim sine As Double
    Dim I As Integer
    Dim cell As Range
    Dim ValRange As Range

    x() = Cells(1, 1).Value

    Cells(1, 1).Value = x(1)
    Cells(2, 1).Value = x(2)
    Cells(3, 1).Value = x(3)
    Cells(4, 1).Value = x(4)
    Cells(5, 1).Value = x(5)
    Cells(6, 1).Value = x(6)

    sine = x(I)
    AddIt = x(I)
    Fact = Fact + 2
    While AddIt < 0.00000001
    sine = AddIt * x(I) * x(I) / Fact / Fact - 1
    AddIt = Abs(AddIt) - 1
    x(I + 1) = x(I)
    Wend



    End Function


    my function is not working
    i need URGENT HELP... Please help me><

    thanks

  2. #2
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    VBAX Guru johnske's Avatar
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    Without testing fully - try...
    [vba]
    Option Explicit

    Sub SinXSeriesExpansion()

    Dim M As Long, N As Long, X As Double, SineX As Double

    X = InputBox("What is X?")
    M = InputBox("How many terms?")

    If IsNumeric(M) And M > 0 Then
    SineX = 0
    On Error GoTo OverFlow
    For N = 0 To M \ 1
    SineX = SineX + ((-1) ^ (N) * X ^ (2 * N + 1)) / Evaluate("Fact(" & 2 * N + 1 & ")")
    Range("A" & N + 1) = SineX
    Next
    MsgBox SineX
    Else
    MsgBox "Need the number of terms to be greater than zero!"
    End If
    Exit Sub

    OverFlow:
    MsgBox "Too many terms - try fewer terms", , "OverFlow Error!!"
    End Sub
    [/vba]
    You know you're really in trouble when the light at the end of the tunnel turns out to be the headlight of a train hurtling towards you

    The major part of getting the right answer lies in asking the right question...


    Made your code more readable, use VBA tags (this automatically inserts [vba] at the start of your code, and [/vba ] at the end of your code) | Help those helping you by marking your thread solved when it is.

  3. #3
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    sorry
    but can i hav it as a While Loop program?
    coz my lecturer is asking me for a while loop...><
    Thank you alot for helping me out...><

  4. #4
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    VP-Knowledge Base VBAX Grand Master mdmackillop's Avatar
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    Please read this from FAQ
    MVP (Excel 2008-2010)

    Post a workbook with sample data and layout if you want a quicker solution.


    To help indent your macros try Smart Indent

    Please remember to mark threads 'Solved'

  5. #5
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    Chat VP VBAX Guru johnske's Avatar
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    So it's homework is it? We don't do homework.
    You know you're really in trouble when the light at the end of the tunnel turns out to be the headlight of a train hurtling towards you

    The major part of getting the right answer lies in asking the right question...


    Made your code more readable, use VBA tags (this automatically inserts [vba] at the start of your code, and [/vba ] at the end of your code) | Help those helping you by marking your thread solved when it is.

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